Yaʿqob I was a legendary primate of the Church of the East, from the family of Joseph the carpenter, who is conventionally believed to have reigned c.190.
Brief accounts of the life of Yaʿqob are given in the Ecclesiastical Chronicle of the Jacobite writer Bar Hebraeus (floruit 1280) and in the ecclesiastical histories of the Nestorian writers Mari (twelfth-century), ʿAmr (fourteenth-century) and Sliba (fourteenth-century).
[1] The following account of the life of Yaʿqob is given by Mari: Yaʿqob, a Hebrew, from the family of Joseph, the husband of Mary, was sent from Jerusalem after he had modestly attempted to refuse such a dignity, pleading that he was too humble to accept an office which he later fulfilled splendidly.
In his time there flourished the second empire of Persia, and the city of Ardashir was built and named after its king.
Yaʿqob died after ruling the church for eighteen years and six months, and was buried in al-Madaʿin.